The applicants intend to continue research on the chemistry of collagen and elastin crosslinking (maturation). They have shown that the crosslinks related to the desmosines which are capable of crosslinking as many as four chains, are present in a wide variety of isomeric forms as well as at different oxidation levels. Current work attempts to separate and characterize these isomers and related compounds. In the case of the cross-linking compounds in collagen, it is now apparent that specific tissues have characteristic crosslinking patterns. In certain pathological situations, it appears that collagen maturation patterns are altered. In order to examine "pathological" collagen, "fingerprinting" techniques are being developed which allow the investigators to focus on specific special features of the collagen molecule. Techniques have been, and are being developed to look at the distribution of hydroxyproline and hydroxylsine throughout the entire collagen backbone. A new method based on the reaction of radioactive cyanide with the aldehydic components of collagen and elastin has been reported by the applicants and is being employed in their current investigation.